View Javadoc
1   /*
2    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3    *
4    * This code is free software; you can redistribute it and/or modify it
5    * under the terms of the GNU General Public License version 2 only, as
6    * published by the Free Software Foundation.  Oracle designates this
7    * particular file as subject to the "Classpath" exception as provided
8    * by Oracle in the LICENSE file that accompanied this code.
9    *
10   * This code is distributed in the hope that it will be useful, but WITHOUT
11   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
13   * version 2 for more details (a copy is included in the LICENSE file that
14   * accompanied this code).
15   *
16   * You should have received a copy of the GNU General Public License version
17   * 2 along with this work; if not, write to the Free Software Foundation,
18   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19   *
20   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21   * or visit www.oracle.com if you need additional information or have any
22   * questions.
23   */
24  
25  /*
26   * This file is available under and governed by the GNU General Public
27   * License version 2 only, as published by the Free Software Foundation.
28   * However, the following notice accompanied the original version of this
29   * file:
30   *
31   * ASM: a very small and fast Java bytecode manipulation framework
32   * Copyright (c) 2000-2011 INRIA, France Telecom
33   * All rights reserved.
34   *
35   * Redistribution and use in source and binary forms, with or without
36   * modification, are permitted provided that the following conditions
37   * are met:
38   * 1. Redistributions of source code must retain the above copyright
39   *    notice, this list of conditions and the following disclaimer.
40   * 2. Redistributions in binary form must reproduce the above copyright
41   *    notice, this list of conditions and the following disclaimer in the
42   *    documentation and/or other materials provided with the distribution.
43   * 3. Neither the name of the copyright holders nor the names of its
44   *    contributors may be used to endorse or promote products derived from
45   *    this software without specific prior written permission.
46   *
47   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
48   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
49   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
50   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
51   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
52   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
53   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
54   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
55   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
56   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
57   * THE POSSIBILITY OF SUCH DAMAGE.
58   */
59  package jdk.internal.org.objectweb.asm;
60  
61  /**
62   * A {@link ClassVisitor} that generates classes in bytecode form. More
63   * precisely this visitor generates a byte array conforming to the Java class
64   * file format. It can be used alone, to generate a Java class "from scratch",
65   * or with one or more {@link ClassReader ClassReader} and adapter class visitor
66   * to generate a modified class from one or more existing Java classes.
67   *
68   * @author Eric Bruneton
69   */
70  public class ClassWriter extends ClassVisitor {
71  
72      /**
73       * Flag to automatically compute the maximum stack size and the maximum
74       * number of local variables of methods. If this flag is set, then the
75       * arguments of the {@link MethodVisitor#visitMaxs visitMaxs} method of the
76       * {@link MethodVisitor} returned by the {@link #visitMethod visitMethod}
77       * method will be ignored, and computed automatically from the signature and
78       * the bytecode of each method.
79       *
80       * @see #ClassWriter(int)
81       */
82      public static final int COMPUTE_MAXS = 1;
83  
84      /**
85       * Flag to automatically compute the stack map frames of methods from
86       * scratch. If this flag is set, then the calls to the
87       * {@link MethodVisitor#visitFrame} method are ignored, and the stack map
88       * frames are recomputed from the methods bytecode. The arguments of the
89       * {@link MethodVisitor#visitMaxs visitMaxs} method are also ignored and
90       * recomputed from the bytecode. In other words, computeFrames implies
91       * computeMaxs.
92       *
93       * @see #ClassWriter(int)
94       */
95      public static final int COMPUTE_FRAMES = 2;
96  
97      /**
98       * Pseudo access flag to distinguish between the synthetic attribute and the
99       * synthetic access flag.
100      */
101     static final int ACC_SYNTHETIC_ATTRIBUTE = 0x40000;
102 
103     /**
104      * Factor to convert from ACC_SYNTHETIC_ATTRIBUTE to Opcode.ACC_SYNTHETIC.
105      */
106     static final int TO_ACC_SYNTHETIC = ACC_SYNTHETIC_ATTRIBUTE
107             / Opcodes.ACC_SYNTHETIC;
108 
109     /**
110      * The type of instructions without any argument.
111      */
112     static final int NOARG_INSN = 0;
113 
114     /**
115      * The type of instructions with an signed byte argument.
116      */
117     static final int SBYTE_INSN = 1;
118 
119     /**
120      * The type of instructions with an signed short argument.
121      */
122     static final int SHORT_INSN = 2;
123 
124     /**
125      * The type of instructions with a local variable index argument.
126      */
127     static final int VAR_INSN = 3;
128 
129     /**
130      * The type of instructions with an implicit local variable index argument.
131      */
132     static final int IMPLVAR_INSN = 4;
133 
134     /**
135      * The type of instructions with a type descriptor argument.
136      */
137     static final int TYPE_INSN = 5;
138 
139     /**
140      * The type of field and method invocations instructions.
141      */
142     static final int FIELDORMETH_INSN = 6;
143 
144     /**
145      * The type of the INVOKEINTERFACE/INVOKEDYNAMIC instruction.
146      */
147     static final int ITFMETH_INSN = 7;
148 
149     /**
150      * The type of the INVOKEDYNAMIC instruction.
151      */
152     static final int INDYMETH_INSN = 8;
153 
154     /**
155      * The type of instructions with a 2 bytes bytecode offset label.
156      */
157     static final int LABEL_INSN = 9;
158 
159     /**
160      * The type of instructions with a 4 bytes bytecode offset label.
161      */
162     static final int LABELW_INSN = 10;
163 
164     /**
165      * The type of the LDC instruction.
166      */
167     static final int LDC_INSN = 11;
168 
169     /**
170      * The type of the LDC_W and LDC2_W instructions.
171      */
172     static final int LDCW_INSN = 12;
173 
174     /**
175      * The type of the IINC instruction.
176      */
177     static final int IINC_INSN = 13;
178 
179     /**
180      * The type of the TABLESWITCH instruction.
181      */
182     static final int TABL_INSN = 14;
183 
184     /**
185      * The type of the LOOKUPSWITCH instruction.
186      */
187     static final int LOOK_INSN = 15;
188 
189     /**
190      * The type of the MULTIANEWARRAY instruction.
191      */
192     static final int MANA_INSN = 16;
193 
194     /**
195      * The type of the WIDE instruction.
196      */
197     static final int WIDE_INSN = 17;
198 
199     /**
200      * The instruction types of all JVM opcodes.
201      */
202     static final byte[] TYPE;
203 
204     /**
205      * The type of CONSTANT_Class constant pool items.
206      */
207     static final int CLASS = 7;
208 
209     /**
210      * The type of CONSTANT_Fieldref constant pool items.
211      */
212     static final int FIELD = 9;
213 
214     /**
215      * The type of CONSTANT_Methodref constant pool items.
216      */
217     static final int METH = 10;
218 
219     /**
220      * The type of CONSTANT_InterfaceMethodref constant pool items.
221      */
222     static final int IMETH = 11;
223 
224     /**
225      * The type of CONSTANT_String constant pool items.
226      */
227     static final int STR = 8;
228 
229     /**
230      * The type of CONSTANT_Integer constant pool items.
231      */
232     static final int INT = 3;
233 
234     /**
235      * The type of CONSTANT_Float constant pool items.
236      */
237     static final int FLOAT = 4;
238 
239     /**
240      * The type of CONSTANT_Long constant pool items.
241      */
242     static final int LONG = 5;
243 
244     /**
245      * The type of CONSTANT_Double constant pool items.
246      */
247     static final int DOUBLE = 6;
248 
249     /**
250      * The type of CONSTANT_NameAndType constant pool items.
251      */
252     static final int NAME_TYPE = 12;
253 
254     /**
255      * The type of CONSTANT_Utf8 constant pool items.
256      */
257     static final int UTF8 = 1;
258 
259     /**
260      * The type of CONSTANT_MethodType constant pool items.
261      */
262     static final int MTYPE = 16;
263 
264     /**
265      * The type of CONSTANT_MethodHandle constant pool items.
266      */
267     static final int HANDLE = 15;
268 
269     /**
270      * The type of CONSTANT_InvokeDynamic constant pool items.
271      */
272     static final int INDY = 18;
273 
274     /**
275      * The base value for all CONSTANT_MethodHandle constant pool items.
276      * Internally, ASM store the 9 variations of CONSTANT_MethodHandle into 9
277      * different items.
278      */
279     static final int HANDLE_BASE = 20;
280 
281     /**
282      * Normal type Item stored in the ClassWriter {@link ClassWriter#typeTable},
283      * instead of the constant pool, in order to avoid clashes with normal
284      * constant pool items in the ClassWriter constant pool's hash table.
285      */
286     static final int TYPE_NORMAL = 30;
287 
288     /**
289      * Uninitialized type Item stored in the ClassWriter
290      * {@link ClassWriter#typeTable}, instead of the constant pool, in order to
291      * avoid clashes with normal constant pool items in the ClassWriter constant
292      * pool's hash table.
293      */
294     static final int TYPE_UNINIT = 31;
295 
296     /**
297      * Merged type Item stored in the ClassWriter {@link ClassWriter#typeTable},
298      * instead of the constant pool, in order to avoid clashes with normal
299      * constant pool items in the ClassWriter constant pool's hash table.
300      */
301     static final int TYPE_MERGED = 32;
302 
303     /**
304      * The type of BootstrapMethods items. These items are stored in a special
305      * class attribute named BootstrapMethods and not in the constant pool.
306      */
307     static final int BSM = 33;
308 
309     /**
310      * The class reader from which this class writer was constructed, if any.
311      */
312     ClassReader cr;
313 
314     /**
315      * Minor and major version numbers of the class to be generated.
316      */
317     int version;
318 
319     /**
320      * Index of the next item to be added in the constant pool.
321      */
322     int index;
323 
324     /**
325      * The constant pool of this class.
326      */
327     final ByteVector pool;
328 
329     /**
330      * The constant pool's hash table data.
331      */
332     Item[] items;
333 
334     /**
335      * The threshold of the constant pool's hash table.
336      */
337     int threshold;
338 
339     /**
340      * A reusable key used to look for items in the {@link #items} hash table.
341      */
342     final Item key;
343 
344     /**
345      * A reusable key used to look for items in the {@link #items} hash table.
346      */
347     final Item key2;
348 
349     /**
350      * A reusable key used to look for items in the {@link #items} hash table.
351      */
352     final Item key3;
353 
354     /**
355      * A reusable key used to look for items in the {@link #items} hash table.
356      */
357     final Item key4;
358 
359     /**
360      * A type table used to temporarily store internal names that will not
361      * necessarily be stored in the constant pool. This type table is used by
362      * the control flow and data flow analysis algorithm used to compute stack
363      * map frames from scratch. This array associates to each index <tt>i</tt>
364      * the Item whose index is <tt>i</tt>. All Item objects stored in this array
365      * are also stored in the {@link #items} hash table. These two arrays allow
366      * to retrieve an Item from its index or, conversely, to get the index of an
367      * Item from its value. Each Item stores an internal name in its
368      * {@link Item#strVal1} field.
369      */
370     Item[] typeTable;
371 
372     /**
373      * Number of elements in the {@link #typeTable} array.
374      */
375     private short typeCount;
376 
377     /**
378      * The access flags of this class.
379      */
380     private int access;
381 
382     /**
383      * The constant pool item that contains the internal name of this class.
384      */
385     private int name;
386 
387     /**
388      * The internal name of this class.
389      */
390     String thisName;
391 
392     /**
393      * The constant pool item that contains the signature of this class.
394      */
395     private int signature;
396 
397     /**
398      * The constant pool item that contains the internal name of the super class
399      * of this class.
400      */
401     private int superName;
402 
403     /**
404      * Number of interfaces implemented or extended by this class or interface.
405      */
406     private int interfaceCount;
407 
408     /**
409      * The interfaces implemented or extended by this class or interface. More
410      * precisely, this array contains the indexes of the constant pool items
411      * that contain the internal names of these interfaces.
412      */
413     private int[] interfaces;
414 
415     /**
416      * The index of the constant pool item that contains the name of the source
417      * file from which this class was compiled.
418      */
419     private int sourceFile;
420 
421     /**
422      * The SourceDebug attribute of this class.
423      */
424     private ByteVector sourceDebug;
425 
426     /**
427      * The constant pool item that contains the name of the enclosing class of
428      * this class.
429      */
430     private int enclosingMethodOwner;
431 
432     /**
433      * The constant pool item that contains the name and descriptor of the
434      * enclosing method of this class.
435      */
436     private int enclosingMethod;
437 
438     /**
439      * The runtime visible annotations of this class.
440      */
441     private AnnotationWriter anns;
442 
443     /**
444      * The runtime invisible annotations of this class.
445      */
446     private AnnotationWriter ianns;
447 
448     /**
449      * The runtime visible type annotations of this class.
450      */
451     private AnnotationWriter tanns;
452 
453     /**
454      * The runtime invisible type annotations of this class.
455      */
456     private AnnotationWriter itanns;
457 
458     /**
459      * The non standard attributes of this class.
460      */
461     private Attribute attrs;
462 
463     /**
464      * The number of entries in the InnerClasses attribute.
465      */
466     private int innerClassesCount;
467 
468     /**
469      * The InnerClasses attribute.
470      */
471     private ByteVector innerClasses;
472 
473     /**
474      * The number of entries in the BootstrapMethods attribute.
475      */
476     int bootstrapMethodsCount;
477 
478     /**
479      * The BootstrapMethods attribute.
480      */
481     ByteVector bootstrapMethods;
482 
483     /**
484      * The fields of this class. These fields are stored in a linked list of
485      * {@link FieldWriter} objects, linked to each other by their
486      * {@link FieldWriter#fv} field. This field stores the first element of this
487      * list.
488      */
489     FieldWriter firstField;
490 
491     /**
492      * The fields of this class. These fields are stored in a linked list of
493      * {@link FieldWriter} objects, linked to each other by their
494      * {@link FieldWriter#fv} field. This field stores the last element of this
495      * list.
496      */
497     FieldWriter lastField;
498 
499     /**
500      * The methods of this class. These methods are stored in a linked list of
501      * {@link MethodWriter} objects, linked to each other by their
502      * {@link MethodWriter#mv} field. This field stores the first element of
503      * this list.
504      */
505     MethodWriter firstMethod;
506 
507     /**
508      * The methods of this class. These methods are stored in a linked list of
509      * {@link MethodWriter} objects, linked to each other by their
510      * {@link MethodWriter#mv} field. This field stores the last element of this
511      * list.
512      */
513     MethodWriter lastMethod;
514 
515     /**
516      * <tt>true</tt> if the maximum stack size and number of local variables
517      * must be automatically computed.
518      */
519     private boolean computeMaxs;
520 
521     /**
522      * <tt>true</tt> if the stack map frames must be recomputed from scratch.
523      */
524     private boolean computeFrames;
525 
526     /**
527      * <tt>true</tt> if the stack map tables of this class are invalid. The
528      * {@link MethodWriter#resizeInstructions} method cannot transform existing
529      * stack map tables, and so produces potentially invalid classes when it is
530      * executed. In this case the class is reread and rewritten with the
531      * {@link #COMPUTE_FRAMES} option (the resizeInstructions method can resize
532      * stack map tables when this option is used).
533      */
534     boolean invalidFrames;
535 
536     // ------------------------------------------------------------------------
537     // Static initializer
538     // ------------------------------------------------------------------------
539 
540     /**
541      * Computes the instruction types of JVM opcodes.
542      */
543     static {
544         int i;
545         byte[] b = new byte[220];
546         String s = "AAAAAAAAAAAAAAAABCLMMDDDDDEEEEEEEEEEEEEEEEEEEEAAAAAAAADD"
547                 + "DDDEEEEEEEEEEEEEEEEEEEEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
548                 + "AAAAAAAAAAAAAAAAANAAAAAAAAAAAAAAAAAAAAJJJJJJJJJJJJJJJJDOPAA"
549                 + "AAAAGGGGGGGHIFBFAAFFAARQJJKKJJJJJJJJJJJJJJJJJJ";
550         for (i = 0; i < b.length; ++i) {
551             b[i] = (byte) (s.charAt(i) - 'A');
552         }
553         TYPE = b;
554 
555         // code to generate the above string
556         //
557         // // SBYTE_INSN instructions
558         // b[Constants.NEWARRAY] = SBYTE_INSN;
559         // b[Constants.BIPUSH] = SBYTE_INSN;
560         //
561         // // SHORT_INSN instructions
562         // b[Constants.SIPUSH] = SHORT_INSN;
563         //
564         // // (IMPL)VAR_INSN instructions
565         // b[Constants.RET] = VAR_INSN;
566         // for (i = Constants.ILOAD; i <= Constants.ALOAD; ++i) {
567         // b[i] = VAR_INSN;
568         // }
569         // for (i = Constants.ISTORE; i <= Constants.ASTORE; ++i) {
570         // b[i] = VAR_INSN;
571         // }
572         // for (i = 26; i <= 45; ++i) { // ILOAD_0 to ALOAD_3
573         // b[i] = IMPLVAR_INSN;
574         // }
575         // for (i = 59; i <= 78; ++i) { // ISTORE_0 to ASTORE_3
576         // b[i] = IMPLVAR_INSN;
577         // }
578         //
579         // // TYPE_INSN instructions
580         // b[Constants.NEW] = TYPE_INSN;
581         // b[Constants.ANEWARRAY] = TYPE_INSN;
582         // b[Constants.CHECKCAST] = TYPE_INSN;
583         // b[Constants.INSTANCEOF] = TYPE_INSN;
584         //
585         // // (Set)FIELDORMETH_INSN instructions
586         // for (i = Constants.GETSTATIC; i <= Constants.INVOKESTATIC; ++i) {
587         // b[i] = FIELDORMETH_INSN;
588         // }
589         // b[Constants.INVOKEINTERFACE] = ITFMETH_INSN;
590         // b[Constants.INVOKEDYNAMIC] = INDYMETH_INSN;
591         //
592         // // LABEL(W)_INSN instructions
593         // for (i = Constants.IFEQ; i <= Constants.JSR; ++i) {
594         // b[i] = LABEL_INSN;
595         // }
596         // b[Constants.IFNULL] = LABEL_INSN;
597         // b[Constants.IFNONNULL] = LABEL_INSN;
598         // b[200] = LABELW_INSN; // GOTO_W
599         // b[201] = LABELW_INSN; // JSR_W
600         // // temporary opcodes used internally by ASM - see Label and
601         // MethodWriter
602         // for (i = 202; i < 220; ++i) {
603         // b[i] = LABEL_INSN;
604         // }
605         //
606         // // LDC(_W) instructions
607         // b[Constants.LDC] = LDC_INSN;
608         // b[19] = LDCW_INSN; // LDC_W
609         // b[20] = LDCW_INSN; // LDC2_W
610         //
611         // // special instructions
612         // b[Constants.IINC] = IINC_INSN;
613         // b[Constants.TABLESWITCH] = TABL_INSN;
614         // b[Constants.LOOKUPSWITCH] = LOOK_INSN;
615         // b[Constants.MULTIANEWARRAY] = MANA_INSN;
616         // b[196] = WIDE_INSN; // WIDE
617         //
618         // for (i = 0; i < b.length; ++i) {
619         // System.err.print((char)('A' + b[i]));
620         // }
621         // System.err.println();
622     }
623 
624     // ------------------------------------------------------------------------
625     // Constructor
626     // ------------------------------------------------------------------------
627 
628     /**
629      * Constructs a new {@link ClassWriter} object.
630      *
631      * @param flags
632      *            option flags that can be used to modify the default behavior
633      *            of this class. See {@link #COMPUTE_MAXS},
634      *            {@link #COMPUTE_FRAMES}.
635      */
636     public ClassWriter(final int flags) {
637         super(Opcodes.ASM5);
638         index = 1;
639         pool = new ByteVector();
640         items = new Item[256];
641         threshold = (int) (0.75d * items.length);
642         key = new Item();
643         key2 = new Item();
644         key3 = new Item();
645         key4 = new Item();
646         this.computeMaxs = (flags & COMPUTE_MAXS) != 0;
647         this.computeFrames = (flags & COMPUTE_FRAMES) != 0;
648     }
649 
650     /**
651      * Constructs a new {@link ClassWriter} object and enables optimizations for
652      * "mostly add" bytecode transformations. These optimizations are the
653      * following:
654      *
655      * <ul>
656      * <li>The constant pool from the original class is copied as is in the new
657      * class, which saves time. New constant pool entries will be added at the
658      * end if necessary, but unused constant pool entries <i>won't be
659      * removed</i>.</li>
660      * <li>Methods that are not transformed are copied as is in the new class,
661      * directly from the original class bytecode (i.e. without emitting visit
662      * events for all the method instructions), which saves a <i>lot</i> of
663      * time. Untransformed methods are detected by the fact that the
664      * {@link ClassReader} receives {@link MethodVisitor} objects that come from
665      * a {@link ClassWriter} (and not from any other {@link ClassVisitor}
666      * instance).</li>
667      * </ul>
668      *
669      * @param classReader
670      *            the {@link ClassReader} used to read the original class. It
671      *            will be used to copy the entire constant pool from the
672      *            original class and also to copy other fragments of original
673      *            bytecode where applicable.
674      * @param flags
675      *            option flags that can be used to modify the default behavior
676      *            of this class. <i>These option flags do not affect methods
677      *            that are copied as is in the new class. This means that the
678      *            maximum stack size nor the stack frames will be computed for
679      *            these methods</i>. See {@link #COMPUTE_MAXS},
680      *            {@link #COMPUTE_FRAMES}.
681      */
682     public ClassWriter(final ClassReader classReader, final int flags) {
683         this(flags);
684         classReader.copyPool(this);
685         this.cr = classReader;
686     }
687 
688     // ------------------------------------------------------------------------
689     // Implementation of the ClassVisitor abstract class
690     // ------------------------------------------------------------------------
691 
692     @Override
693     public final void visit(final int version, final int access,
694             final String name, final String signature, final String superName,
695             final String[] interfaces) {
696         this.version = version;
697         this.access = access;
698         this.name = newClass(name);
699         thisName = name;
700         if (ClassReader.SIGNATURES && signature != null) {
701             this.signature = newUTF8(signature);
702         }
703         this.superName = superName == null ? 0 : newClass(superName);
704         if (interfaces != null && interfaces.length > 0) {
705             interfaceCount = interfaces.length;
706             this.interfaces = new int[interfaceCount];
707             for (int i = 0; i < interfaceCount; ++i) {
708                 this.interfaces[i] = newClass(interfaces[i]);
709             }
710         }
711     }
712 
713     @Override
714     public final void visitSource(final String file, final String debug) {
715         if (file != null) {
716             sourceFile = newUTF8(file);
717         }
718         if (debug != null) {
719             sourceDebug = new ByteVector().putUTF8(debug);
720         }
721     }
722 
723     @Override
724     public final void visitOuterClass(final String owner, final String name,
725             final String desc) {
726         enclosingMethodOwner = newClass(owner);
727         if (name != null && desc != null) {
728             enclosingMethod = newNameType(name, desc);
729         }
730     }
731 
732     @Override
733     public final AnnotationVisitor visitAnnotation(final String desc,
734             final boolean visible) {
735         if (!ClassReader.ANNOTATIONS) {
736             return null;
737         }
738         ByteVector bv = new ByteVector();
739         // write type, and reserve space for values count
740         bv.putShort(newUTF8(desc)).putShort(0);
741         AnnotationWriter aw = new AnnotationWriter(this, true, bv, bv, 2);
742         if (visible) {
743             aw.next = anns;
744             anns = aw;
745         } else {
746             aw.next = ianns;
747             ianns = aw;
748         }
749         return aw;
750     }
751 
752     @Override
753     public final AnnotationVisitor visitTypeAnnotation(int typeRef,
754             TypePath typePath, final String desc, final boolean visible) {
755         if (!ClassReader.ANNOTATIONS) {
756             return null;
757         }
758         ByteVector bv = new ByteVector();
759         // write target_type and target_info
760         AnnotationWriter.putTarget(typeRef, typePath, bv);
761         // write type, and reserve space for values count
762         bv.putShort(newUTF8(desc)).putShort(0);
763         AnnotationWriter aw = new AnnotationWriter(this, true, bv, bv,
764                 bv.length - 2);
765         if (visible) {
766             aw.next = tanns;
767             tanns = aw;
768         } else {
769             aw.next = itanns;
770             itanns = aw;
771         }
772         return aw;
773     }
774 
775     @Override
776     public final void visitAttribute(final Attribute attr) {
777         attr.next = attrs;
778         attrs = attr;
779     }
780 
781     @Override
782     public final void visitInnerClass(final String name,
783             final String outerName, final String innerName, final int access) {
784         if (innerClasses == null) {
785             innerClasses = new ByteVector();
786         }
787         ++innerClassesCount;
788         innerClasses.putShort(name == null ? 0 : newClass(name));
789         innerClasses.putShort(outerName == null ? 0 : newClass(outerName));
790         innerClasses.putShort(innerName == null ? 0 : newUTF8(innerName));
791         innerClasses.putShort(access);
792     }
793 
794     @Override
795     public final FieldVisitor visitField(final int access, final String name,
796             final String desc, final String signature, final Object value) {
797         return new FieldWriter(this, access, name, desc, signature, value);
798     }
799 
800     @Override
801     public final MethodVisitor visitMethod(final int access, final String name,
802             final String desc, final String signature, final String[] exceptions) {
803         return new MethodWriter(this, access, name, desc, signature,
804                 exceptions, computeMaxs, computeFrames);
805     }
806 
807     @Override
808     public final void visitEnd() {
809     }
810 
811     // ------------------------------------------------------------------------
812     // Other public methods
813     // ------------------------------------------------------------------------
814 
815     /**
816      * Returns the bytecode of the class that was build with this class writer.
817      *
818      * @return the bytecode of the class that was build with this class writer.
819      */
820     public byte[] toByteArray() {
821         if (index > 0xFFFF) {
822             throw new RuntimeException("Class file too large!");
823         }
824         // computes the real size of the bytecode of this class
825         int size = 24 + 2 * interfaceCount;
826         int nbFields = 0;
827         FieldWriter fb = firstField;
828         while (fb != null) {
829             ++nbFields;
830             size += fb.getSize();
831             fb = (FieldWriter) fb.fv;
832         }
833         int nbMethods = 0;
834         MethodWriter mb = firstMethod;
835         while (mb != null) {
836             ++nbMethods;
837             size += mb.getSize();
838             mb = (MethodWriter) mb.mv;
839         }
840         int attributeCount = 0;
841         if (bootstrapMethods != null) {
842             // we put it as first attribute in order to improve a bit
843             // ClassReader.copyBootstrapMethods
844             ++attributeCount;
845             size += 8 + bootstrapMethods.length;
846             newUTF8("BootstrapMethods");
847         }
848         if (ClassReader.SIGNATURES && signature != 0) {
849             ++attributeCount;
850             size += 8;
851             newUTF8("Signature");
852         }
853         if (sourceFile != 0) {
854             ++attributeCount;
855             size += 8;
856             newUTF8("SourceFile");
857         }
858         if (sourceDebug != null) {
859             ++attributeCount;
860             size += sourceDebug.length + 4;
861             newUTF8("SourceDebugExtension");
862         }
863         if (enclosingMethodOwner != 0) {
864             ++attributeCount;
865             size += 10;
866             newUTF8("EnclosingMethod");
867         }
868         if ((access & Opcodes.ACC_DEPRECATED) != 0) {
869             ++attributeCount;
870             size += 6;
871             newUTF8("Deprecated");
872         }
873         if ((access & Opcodes.ACC_SYNTHETIC) != 0) {
874             if ((version & 0xFFFF) < Opcodes.V1_5
875                     || (access & ACC_SYNTHETIC_ATTRIBUTE) != 0) {
876                 ++attributeCount;
877                 size += 6;
878                 newUTF8("Synthetic");
879             }
880         }
881         if (innerClasses != null) {
882             ++attributeCount;
883             size += 8 + innerClasses.length;
884             newUTF8("InnerClasses");
885         }
886         if (ClassReader.ANNOTATIONS && anns != null) {
887             ++attributeCount;
888             size += 8 + anns.getSize();
889             newUTF8("RuntimeVisibleAnnotations");
890         }
891         if (ClassReader.ANNOTATIONS && ianns != null) {
892             ++attributeCount;
893             size += 8 + ianns.getSize();
894             newUTF8("RuntimeInvisibleAnnotations");
895         }
896         if (ClassReader.ANNOTATIONS && tanns != null) {
897             ++attributeCount;
898             size += 8 + tanns.getSize();
899             newUTF8("RuntimeVisibleTypeAnnotations");
900         }
901         if (ClassReader.ANNOTATIONS && itanns != null) {
902             ++attributeCount;
903             size += 8 + itanns.getSize();
904             newUTF8("RuntimeInvisibleTypeAnnotations");
905         }
906         if (attrs != null) {
907             attributeCount += attrs.getCount();
908             size += attrs.getSize(this, null, 0, -1, -1);
909         }
910         size += pool.length;
911         // allocates a byte vector of this size, in order to avoid unnecessary
912         // arraycopy operations in the ByteVector.enlarge() method
913         ByteVector out = new ByteVector(size);
914         out.putInt(0xCAFEBABE).putInt(version);
915         out.putShort(index).putByteArray(pool.data, 0, pool.length);
916         int mask = Opcodes.ACC_DEPRECATED | ACC_SYNTHETIC_ATTRIBUTE
917                 | ((access & ACC_SYNTHETIC_ATTRIBUTE) / TO_ACC_SYNTHETIC);
918         out.putShort(access & ~mask).putShort(name).putShort(superName);
919         out.putShort(interfaceCount);
920         for (int i = 0; i < interfaceCount; ++i) {
921             out.putShort(interfaces[i]);
922         }
923         out.putShort(nbFields);
924         fb = firstField;
925         while (fb != null) {
926             fb.put(out);
927             fb = (FieldWriter) fb.fv;
928         }
929         out.putShort(nbMethods);
930         mb = firstMethod;
931         while (mb != null) {
932             mb.put(out);
933             mb = (MethodWriter) mb.mv;
934         }
935         out.putShort(attributeCount);
936         if (bootstrapMethods != null) {
937             out.putShort(newUTF8("BootstrapMethods"));
938             out.putInt(bootstrapMethods.length + 2).putShort(
939                     bootstrapMethodsCount);
940             out.putByteArray(bootstrapMethods.data, 0, bootstrapMethods.length);
941         }
942         if (ClassReader.SIGNATURES && signature != 0) {
943             out.putShort(newUTF8("Signature")).putInt(2).putShort(signature);
944         }
945         if (sourceFile != 0) {
946             out.putShort(newUTF8("SourceFile")).putInt(2).putShort(sourceFile);
947         }
948         if (sourceDebug != null) {
949             int len = sourceDebug.length - 2;
950             out.putShort(newUTF8("SourceDebugExtension")).putInt(len);
951             out.putByteArray(sourceDebug.data, 2, len);
952         }
953         if (enclosingMethodOwner != 0) {
954             out.putShort(newUTF8("EnclosingMethod")).putInt(4);
955             out.putShort(enclosingMethodOwner).putShort(enclosingMethod);
956         }
957         if ((access & Opcodes.ACC_DEPRECATED) != 0) {
958             out.putShort(newUTF8("Deprecated")).putInt(0);
959         }
960         if ((access & Opcodes.ACC_SYNTHETIC) != 0) {
961             if ((version & 0xFFFF) < Opcodes.V1_5
962                     || (access & ACC_SYNTHETIC_ATTRIBUTE) != 0) {
963                 out.putShort(newUTF8("Synthetic")).putInt(0);
964             }
965         }
966         if (innerClasses != null) {
967             out.putShort(newUTF8("InnerClasses"));
968             out.putInt(innerClasses.length + 2).putShort(innerClassesCount);
969             out.putByteArray(innerClasses.data, 0, innerClasses.length);
970         }
971         if (ClassReader.ANNOTATIONS && anns != null) {
972             out.putShort(newUTF8("RuntimeVisibleAnnotations"));
973             anns.put(out);
974         }
975         if (ClassReader.ANNOTATIONS && ianns != null) {
976             out.putShort(newUTF8("RuntimeInvisibleAnnotations"));
977             ianns.put(out);
978         }
979         if (ClassReader.ANNOTATIONS && tanns != null) {
980             out.putShort(newUTF8("RuntimeVisibleTypeAnnotations"));
981             tanns.put(out);
982         }
983         if (ClassReader.ANNOTATIONS && itanns != null) {
984             out.putShort(newUTF8("RuntimeInvisibleTypeAnnotations"));
985             itanns.put(out);
986         }
987         if (attrs != null) {
988             attrs.put(this, null, 0, -1, -1, out);
989         }
990         if (invalidFrames) {
991             anns = null;
992             ianns = null;
993             attrs = null;
994             innerClassesCount = 0;
995             innerClasses = null;
996             bootstrapMethodsCount = 0;
997             bootstrapMethods = null;
998             firstField = null;
999             lastField = null;
1000             firstMethod = null;
1001             lastMethod = null;
1002             computeMaxs = false;
1003             computeFrames = true;
1004             invalidFrames = false;
1005             new ClassReader(out.data).accept(this, ClassReader.SKIP_FRAMES);
1006             return toByteArray();
1007         }
1008         return out.data;
1009     }
1010 
1011     // ------------------------------------------------------------------------
1012     // Utility methods: constant pool management
1013     // ------------------------------------------------------------------------
1014 
1015     /**
1016      * Adds a number or string constant to the constant pool of the class being
1017      * build. Does nothing if the constant pool already contains a similar item.
1018      *
1019      * @param cst
1020      *            the value of the constant to be added to the constant pool.
1021      *            This parameter must be an {@link Integer}, a {@link Float}, a
1022      *            {@link Long}, a {@link Double}, a {@link String} or a
1023      *            {@link Type}.
1024      * @return a new or already existing constant item with the given value.
1025      */
1026     Item newConstItem(final Object cst) {
1027         if (cst instanceof Integer) {
1028             int val = ((Integer) cst).intValue();
1029             return newInteger(val);
1030         } else if (cst instanceof Byte) {
1031             int val = ((Byte) cst).intValue();
1032             return newInteger(val);
1033         } else if (cst instanceof Character) {
1034             int val = ((Character) cst).charValue();
1035             return newInteger(val);
1036         } else if (cst instanceof Short) {
1037             int val = ((Short) cst).intValue();
1038             return newInteger(val);
1039         } else if (cst instanceof Boolean) {
1040             int val = ((Boolean) cst).booleanValue() ? 1 : 0;
1041             return newInteger(val);
1042         } else if (cst instanceof Float) {
1043             float val = ((Float) cst).floatValue();
1044             return newFloat(val);
1045         } else if (cst instanceof Long) {
1046             long val = ((Long) cst).longValue();
1047             return newLong(val);
1048         } else if (cst instanceof Double) {
1049             double val = ((Double) cst).doubleValue();
1050             return newDouble(val);
1051         } else if (cst instanceof String) {
1052             return newString((String) cst);
1053         } else if (cst instanceof Type) {
1054             Type t = (Type) cst;
1055             int s = t.getSort();
1056             if (s == Type.OBJECT) {
1057                 return newClassItem(t.getInternalName());
1058             } else if (s == Type.METHOD) {
1059                 return newMethodTypeItem(t.getDescriptor());
1060             } else { // s == primitive type or array
1061                 return newClassItem(t.getDescriptor());
1062             }
1063         } else if (cst instanceof Handle) {
1064             Handle h = (Handle) cst;
1065             return newHandleItem(h.tag, h.owner, h.name, h.desc);
1066         } else {
1067             throw new IllegalArgumentException("value " + cst);
1068         }
1069     }
1070 
1071     /**
1072      * Adds a number or string constant to the constant pool of the class being
1073      * build. Does nothing if the constant pool already contains a similar item.
1074      * <i>This method is intended for {@link Attribute} sub classes, and is
1075      * normally not needed by class generators or adapters.</i>
1076      *
1077      * @param cst
1078      *            the value of the constant to be added to the constant pool.
1079      *            This parameter must be an {@link Integer}, a {@link Float}, a
1080      *            {@link Long}, a {@link Double} or a {@link String}.
1081      * @return the index of a new or already existing constant item with the
1082      *         given value.
1083      */
1084     public int newConst(final Object cst) {
1085         return newConstItem(cst).index;
1086     }
1087 
1088     /**
1089      * Adds an UTF8 string to the constant pool of the class being build. Does
1090      * nothing if the constant pool already contains a similar item. <i>This
1091      * method is intended for {@link Attribute} sub classes, and is normally not
1092      * needed by class generators or adapters.</i>
1093      *
1094      * @param value
1095      *            the String value.
1096      * @return the index of a new or already existing UTF8 item.
1097      */
1098     public int newUTF8(final String value) {
1099         key.set(UTF8, value, null, null);
1100         Item result = get(key);
1101         if (result == null) {
1102             pool.putByte(UTF8).putUTF8(value);
1103             result = new Item(index++, key);
1104             put(result);
1105         }
1106         return result.index;
1107     }
1108 
1109     /**
1110      * Adds a class reference to the constant pool of the class being build.
1111      * Does nothing if the constant pool already contains a similar item.
1112      * <i>This method is intended for {@link Attribute} sub classes, and is
1113      * normally not needed by class generators or adapters.</i>
1114      *
1115      * @param value
1116      *            the internal name of the class.
1117      * @return a new or already existing class reference item.
1118      */
1119     Item newClassItem(final String value) {
1120         key2.set(CLASS, value, null, null);
1121         Item result = get(key2);
1122         if (result == null) {
1123             pool.put12(CLASS, newUTF8(value));
1124             result = new Item(index++, key2);
1125             put(result);
1126         }
1127         return result;
1128     }
1129 
1130     /**
1131      * Adds a class reference to the constant pool of the class being build.
1132      * Does nothing if the constant pool already contains a similar item.
1133      * <i>This method is intended for {@link Attribute} sub classes, and is
1134      * normally not needed by class generators or adapters.</i>
1135      *
1136      * @param value
1137      *            the internal name of the class.
1138      * @return the index of a new or already existing class reference item.
1139      */
1140     public int newClass(final String value) {
1141         return newClassItem(value).index;
1142     }
1143 
1144     /**
1145      * Adds a method type reference to the constant pool of the class being
1146      * build. Does nothing if the constant pool already contains a similar item.
1147      * <i>This method is intended for {@link Attribute} sub classes, and is
1148      * normally not needed by class generators or adapters.</i>
1149      *
1150      * @param methodDesc
1151      *            method descriptor of the method type.
1152      * @return a new or already existing method type reference item.
1153      */
1154     Item newMethodTypeItem(final String methodDesc) {
1155         key2.set(MTYPE, methodDesc, null, null);
1156         Item result = get(key2);
1157         if (result == null) {
1158             pool.put12(MTYPE, newUTF8(methodDesc));
1159             result = new Item(index++, key2);
1160             put(result);
1161         }
1162         return result;
1163     }
1164 
1165     /**
1166      * Adds a method type reference to the constant pool of the class being
1167      * build. Does nothing if the constant pool already contains a similar item.
1168      * <i>This method is intended for {@link Attribute} sub classes, and is
1169      * normally not needed by class generators or adapters.</i>
1170      *
1171      * @param methodDesc
1172      *            method descriptor of the method type.
1173      * @return the index of a new or already existing method type reference
1174      *         item.
1175      */
1176     public int newMethodType(final String methodDesc) {
1177         return newMethodTypeItem(methodDesc).index;
1178     }
1179 
1180     /**
1181      * Adds a handle to the constant pool of the class being build. Does nothing
1182      * if the constant pool already contains a similar item. <i>This method is
1183      * intended for {@link Attribute} sub classes, and is normally not needed by
1184      * class generators or adapters.</i>
1185      *
1186      * @param tag
1187      *            the kind of this handle. Must be {@link Opcodes#H_GETFIELD},
1188      *            {@link Opcodes#H_GETSTATIC}, {@link Opcodes#H_PUTFIELD},
1189      *            {@link Opcodes#H_PUTSTATIC}, {@link Opcodes#H_INVOKEVIRTUAL},
1190      *            {@link Opcodes#H_INVOKESTATIC},
1191      *            {@link Opcodes#H_INVOKESPECIAL},
1192      *            {@link Opcodes#H_NEWINVOKESPECIAL} or
1193      *            {@link Opcodes#H_INVOKEINTERFACE}.
1194      * @param owner
1195      *            the internal name of the field or method owner class.
1196      * @param name
1197      *            the name of the field or method.
1198      * @param desc
1199      *            the descriptor of the field or method.
1200      * @return a new or an already existing method type reference item.
1201      */
1202     Item newHandleItem(final int tag, final String owner, final String name,
1203             final String desc) {
1204         key4.set(HANDLE_BASE + tag, owner, name, desc);
1205         Item result = get(key4);
1206         if (result == null) {
1207             if (tag <= Opcodes.H_PUTSTATIC) {
1208                 put112(HANDLE, tag, newField(owner, name, desc));
1209             } else {
1210                 put112(HANDLE,
1211                         tag,
1212                         newMethod(owner, name, desc,
1213                                 tag == Opcodes.H_INVOKEINTERFACE));
1214             }
1215             result = new Item(index++, key4);
1216             put(result);
1217         }
1218         return result;
1219     }
1220 
1221     /**
1222      * Adds a handle to the constant pool of the class being build. Does nothing
1223      * if the constant pool already contains a similar item. <i>This method is
1224      * intended for {@link Attribute} sub classes, and is normally not needed by
1225      * class generators or adapters.</i>
1226      *
1227      * @param tag
1228      *            the kind of this handle. Must be {@link Opcodes#H_GETFIELD},
1229      *            {@link Opcodes#H_GETSTATIC}, {@link Opcodes#H_PUTFIELD},
1230      *            {@link Opcodes#H_PUTSTATIC}, {@link Opcodes#H_INVOKEVIRTUAL},
1231      *            {@link Opcodes#H_INVOKESTATIC},
1232      *            {@link Opcodes#H_INVOKESPECIAL},
1233      *            {@link Opcodes#H_NEWINVOKESPECIAL} or
1234      *            {@link Opcodes#H_INVOKEINTERFACE}.
1235      * @param owner
1236      *            the internal name of the field or method owner class.
1237      * @param name
1238      *            the name of the field or method.
1239      * @param desc
1240      *            the descriptor of the field or method.
1241      * @return the index of a new or already existing method type reference
1242      *         item.
1243      */
1244     public int newHandle(final int tag, final String owner, final String name,
1245             final String desc) {
1246         return newHandleItem(tag, owner, name, desc).index;
1247     }
1248 
1249     /**
1250      * Adds an invokedynamic reference to the constant pool of the class being
1251      * build. Does nothing if the constant pool already contains a similar item.
1252      * <i>This method is intended for {@link Attribute} sub classes, and is
1253      * normally not needed by class generators or adapters.</i>
1254      *
1255      * @param name
1256      *            name of the invoked method.
1257      * @param desc
1258      *            descriptor of the invoke method.
1259      * @param bsm
1260      *            the bootstrap method.
1261      * @param bsmArgs
1262      *            the bootstrap method constant arguments.
1263      *
1264      * @return a new or an already existing invokedynamic type reference item.
1265      */
1266     Item newInvokeDynamicItem(final String name, final String desc,
1267             final Handle bsm, final Object... bsmArgs) {
1268         // cache for performance
1269         ByteVector bootstrapMethods = this.bootstrapMethods;
1270         if (bootstrapMethods == null) {
1271             bootstrapMethods = this.bootstrapMethods = new ByteVector();
1272         }
1273 
1274         int position = bootstrapMethods.length; // record current position
1275 
1276         int hashCode = bsm.hashCode();
1277         bootstrapMethods.putShort(newHandle(bsm.tag, bsm.owner, bsm.name,
1278                 bsm.desc));
1279 
1280         int argsLength = bsmArgs.length;
1281         bootstrapMethods.putShort(argsLength);
1282 
1283         for (int i = 0; i < argsLength; i++) {
1284             Object bsmArg = bsmArgs[i];
1285             hashCode ^= bsmArg.hashCode();
1286             bootstrapMethods.putShort(newConst(bsmArg));
1287         }
1288 
1289         byte[] data = bootstrapMethods.data;
1290         int length = (1 + 1 + argsLength) << 1; // (bsm + argCount + arguments)
1291         hashCode &= 0x7FFFFFFF;
1292         Item result = items[hashCode % items.length];
1293         loop: while (result != null) {
1294             if (result.type != BSM || result.hashCode != hashCode) {
1295                 result = result.next;
1296                 continue;
1297             }
1298 
1299             // because the data encode the size of the argument
1300             // we don't need to test if these size are equals
1301             int resultPosition = result.intVal;
1302             for (int p = 0; p < length; p++) {
1303                 if (data[position + p] != data[resultPosition + p]) {
1304                     result = result.next;
1305                     continue loop;
1306                 }
1307             }
1308             break;
1309         }
1310 
1311         int bootstrapMethodIndex;
1312         if (result != null) {
1313             bootstrapMethodIndex = result.index;
1314             bootstrapMethods.length = position; // revert to old position
1315         } else {
1316             bootstrapMethodIndex = bootstrapMethodsCount++;
1317             result = new Item(bootstrapMethodIndex);
1318             result.set(position, hashCode);
1319             put(result);
1320         }
1321 
1322         // now, create the InvokeDynamic constant
1323         key3.set(name, desc, bootstrapMethodIndex);
1324         result = get(key3);
1325         if (result == null) {
1326             put122(INDY, bootstrapMethodIndex, newNameType(name, desc));
1327             result = new Item(index++, key3);
1328             put(result);
1329         }
1330         return result;
1331     }
1332 
1333     /**
1334      * Adds an invokedynamic reference to the constant pool of the class being
1335      * build. Does nothing if the constant pool already contains a similar item.
1336      * <i>This method is intended for {@link Attribute} sub classes, and is
1337      * normally not needed by class generators or adapters.</i>
1338      *
1339      * @param name
1340      *            name of the invoked method.
1341      * @param desc
1342      *            descriptor of the invoke method.
1343      * @param bsm
1344      *            the bootstrap method.
1345      * @param bsmArgs
1346      *            the bootstrap method constant arguments.
1347      *
1348      * @return the index of a new or already existing invokedynamic reference
1349      *         item.
1350      */
1351     public int newInvokeDynamic(final String name, final String desc,
1352             final Handle bsm, final Object... bsmArgs) {
1353         return newInvokeDynamicItem(name, desc, bsm, bsmArgs).index;
1354     }
1355 
1356     /**
1357      * Adds a field reference to the constant pool of the class being build.
1358      * Does nothing if the constant pool already contains a similar item.
1359      *
1360      * @param owner
1361      *            the internal name of the field's owner class.
1362      * @param name
1363      *            the field's name.
1364      * @param desc
1365      *            the field's descriptor.
1366      * @return a new or already existing field reference item.
1367      */
1368     Item newFieldItem(final String owner, final String name, final String desc) {
1369         key3.set(FIELD, owner, name, desc);
1370         Item result = get(key3);
1371         if (result == null) {
1372             put122(FIELD, newClass(owner), newNameType(name, desc));
1373             result = new Item(index++, key3);
1374             put(result);
1375         }
1376         return result;
1377     }
1378 
1379     /**
1380      * Adds a field reference to the constant pool of the class being build.
1381      * Does nothing if the constant pool already contains a similar item.
1382      * <i>This method is intended for {@link Attribute} sub classes, and is
1383      * normally not needed by class generators or adapters.</i>
1384      *
1385      * @param owner
1386      *            the internal name of the field's owner class.
1387      * @param name
1388      *            the field's name.
1389      * @param desc
1390      *            the field's descriptor.
1391      * @return the index of a new or already existing field reference item.
1392      */
1393     public int newField(final String owner, final String name, final String desc) {
1394         return newFieldItem(owner, name, desc).index;
1395     }
1396 
1397     /**
1398      * Adds a method reference to the constant pool of the class being build.
1399      * Does nothing if the constant pool already contains a similar item.
1400      *
1401      * @param owner
1402      *            the internal name of the method's owner class.
1403      * @param name
1404      *            the method's name.
1405      * @param desc
1406      *            the method's descriptor.
1407      * @param itf
1408      *            <tt>true</tt> if <tt>owner</tt> is an interface.
1409      * @return a new or already existing method reference item.
1410      */
1411     Item newMethodItem(final String owner, final String name,
1412             final String desc, final boolean itf) {
1413         int type = itf ? IMETH : METH;
1414         key3.set(type, owner, name, desc);
1415         Item result = get(key3);
1416         if (result == null) {
1417             put122(type, newClass(owner), newNameType(name, desc));
1418             result = new Item(index++, key3);
1419             put(result);
1420         }
1421         return result;
1422     }
1423 
1424     /**
1425      * Adds a method reference to the constant pool of the class being build.
1426      * Does nothing if the constant pool already contains a similar item.
1427      * <i>This method is intended for {@link Attribute} sub classes, and is
1428      * normally not needed by class generators or adapters.</i>
1429      *
1430      * @param owner
1431      *            the internal name of the method's owner class.
1432      * @param name
1433      *            the method's name.
1434      * @param desc
1435      *            the method's descriptor.
1436      * @param itf
1437      *            <tt>true</tt> if <tt>owner</tt> is an interface.
1438      * @return the index of a new or already existing method reference item.
1439      */
1440     public int newMethod(final String owner, final String name,
1441             final String desc, final boolean itf) {
1442         return newMethodItem(owner, name, desc, itf).index;
1443     }
1444 
1445     /**
1446      * Adds an integer to the constant pool of the class being build. Does
1447      * nothing if the constant pool already contains a similar item.
1448      *
1449      * @param value
1450      *            the int value.
1451      * @return a new or already existing int item.
1452      */
1453     Item newInteger(final int value) {
1454         key.set(value);
1455         Item result = get(key);
1456         if (result == null) {
1457             pool.putByte(INT).putInt(value);
1458             result = new Item(index++, key);
1459             put(result);
1460         }
1461         return result;
1462     }
1463 
1464     /**
1465      * Adds a float to the constant pool of the class being build. Does nothing
1466      * if the constant pool already contains a similar item.
1467      *
1468      * @param value
1469      *            the float value.
1470      * @return a new or already existing float item.
1471      */
1472     Item newFloat(final float value) {
1473         key.set(value);
1474         Item result = get(key);
1475         if (result == null) {
1476             pool.putByte(FLOAT).putInt(key.intVal);
1477             result = new Item(index++, key);
1478             put(result);
1479         }
1480         return result;
1481     }
1482 
1483     /**
1484      * Adds a long to the constant pool of the class being build. Does nothing
1485      * if the constant pool already contains a similar item.
1486      *
1487      * @param value
1488      *            the long value.
1489      * @return a new or already existing long item.
1490      */
1491     Item newLong(final long value) {
1492         key.set(value);
1493         Item result = get(key);
1494         if (result == null) {
1495             pool.putByte(LONG).putLong(value);
1496             result = new Item(index, key);
1497             index += 2;
1498             put(result);
1499         }
1500         return result;
1501     }
1502 
1503     /**
1504      * Adds a double to the constant pool of the class being build. Does nothing
1505      * if the constant pool already contains a similar item.
1506      *
1507      * @param value
1508      *            the double value.
1509      * @return a new or already existing double item.
1510      */
1511     Item newDouble(final double value) {
1512         key.set(value);
1513         Item result = get(key);
1514         if (result == null) {
1515             pool.putByte(DOUBLE).putLong(key.longVal);
1516             result = new Item(index, key);
1517             index += 2;
1518             put(result);
1519         }
1520         return result;
1521     }
1522 
1523     /**
1524      * Adds a string to the constant pool of the class being build. Does nothing
1525      * if the constant pool already contains a similar item.
1526      *
1527      * @param value
1528      *            the String value.
1529      * @return a new or already existing string item.
1530      */
1531     private Item newString(final String value) {
1532         key2.set(STR, value, null, null);
1533         Item result = get(key2);
1534         if (result == null) {
1535             pool.put12(STR, newUTF8(value));
1536             result = new Item(index++, key2);
1537             put(result);
1538         }
1539         return result;
1540     }
1541 
1542     /**
1543      * Adds a name and type to the constant pool of the class being build. Does
1544      * nothing if the constant pool already contains a similar item. <i>This
1545      * method is intended for {@link Attribute} sub classes, and is normally not
1546      * needed by class generators or adapters.</i>
1547      *
1548      * @param name
1549      *            a name.
1550      * @param desc
1551      *            a type descriptor.
1552      * @return the index of a new or already existing name and type item.
1553      */
1554     public int newNameType(final String name, final String desc) {
1555         return newNameTypeItem(name, desc).index;
1556     }
1557 
1558     /**
1559      * Adds a name and type to the constant pool of the class being build. Does
1560      * nothing if the constant pool already contains a similar item.
1561      *
1562      * @param name
1563      *            a name.
1564      * @param desc
1565      *            a type descriptor.
1566      * @return a new or already existing name and type item.
1567      */
1568     Item newNameTypeItem(final String name, final String desc) {
1569         key2.set(NAME_TYPE, name, desc, null);
1570         Item result = get(key2);
1571         if (result == null) {
1572             put122(NAME_TYPE, newUTF8(name), newUTF8(desc));
1573             result = new Item(index++, key2);
1574             put(result);
1575         }
1576         return result;
1577     }
1578 
1579     /**
1580      * Adds the given internal name to {@link #typeTable} and returns its index.
1581      * Does nothing if the type table already contains this internal name.
1582      *
1583      * @param type
1584      *            the internal name to be added to the type table.
1585      * @return the index of this internal name in the type table.
1586      */
1587     int addType(final String type) {
1588         key.set(TYPE_NORMAL, type, null, null);
1589         Item result = get(key);
1590         if (result == null) {
1591             result = addType(key);
1592         }
1593         return result.index;
1594     }
1595 
1596     /**
1597      * Adds the given "uninitialized" type to {@link #typeTable} and returns its
1598      * index. This method is used for UNINITIALIZED types, made of an internal
1599      * name and a bytecode offset.
1600      *
1601      * @param type
1602      *            the internal name to be added to the type table.
1603      * @param offset
1604      *            the bytecode offset of the NEW instruction that created this
1605      *            UNINITIALIZED type value.
1606      * @return the index of this internal name in the type table.
1607      */
1608     int addUninitializedType(final String type, final int offset) {
1609         key.type = TYPE_UNINIT;
1610         key.intVal = offset;
1611         key.strVal1 = type;
1612         key.hashCode = 0x7FFFFFFF & (TYPE_UNINIT + type.hashCode() + offset);
1613         Item result = get(key);
1614         if (result == null) {
1615             result = addType(key);
1616         }
1617         return result.index;
1618     }
1619 
1620     /**
1621      * Adds the given Item to {@link #typeTable}.
1622      *
1623      * @param item
1624      *            the value to be added to the type table.
1625      * @return the added Item, which a new Item instance with the same value as
1626      *         the given Item.
1627      */
1628     private Item addType(final Item item) {
1629         ++typeCount;
1630         Item result = new Item(typeCount, key);
1631         put(result);
1632         if (typeTable == null) {
1633             typeTable = new Item[16];
1634         }
1635         if (typeCount == typeTable.length) {
1636             Item[] newTable = new Item[2 * typeTable.length];
1637             System.arraycopy(typeTable, 0, newTable, 0, typeTable.length);
1638             typeTable = newTable;
1639         }
1640         typeTable[typeCount] = result;
1641         return result;
1642     }
1643 
1644     /**
1645      * Returns the index of the common super type of the two given types. This
1646      * method calls {@link #getCommonSuperClass} and caches the result in the
1647      * {@link #items} hash table to speedup future calls with the same
1648      * parameters.
1649      *
1650      * @param type1
1651      *            index of an internal name in {@link #typeTable}.
1652      * @param type2
1653      *            index of an internal name in {@link #typeTable}.
1654      * @return the index of the common super type of the two given types.
1655      */
1656     int getMergedType(final int type1, final int type2) {
1657         key2.type = TYPE_MERGED;
1658         key2.longVal = type1 | (((long) type2) << 32);
1659         key2.hashCode = 0x7FFFFFFF & (TYPE_MERGED + type1 + type2);
1660         Item result = get(key2);
1661         if (result == null) {
1662             String t = typeTable[type1].strVal1;
1663             String u = typeTable[type2].strVal1;
1664             key2.intVal = addType(getCommonSuperClass(t, u));
1665             result = new Item((short) 0, key2);
1666             put(result);
1667         }
1668         return result.intVal;
1669     }
1670 
1671     /**
1672      * Returns the common super type of the two given types. The default
1673      * implementation of this method <i>loads</i> the two given classes and uses
1674      * the java.lang.Class methods to find the common super class. It can be
1675      * overridden to compute this common super type in other ways, in particular
1676      * without actually loading any class, or to take into account the class
1677      * that is currently being generated by this ClassWriter, which can of
1678      * course not be loaded since it is under construction.
1679      *
1680      * @param type1
1681      *            the internal name of a class.
1682      * @param type2
1683      *            the internal name of another class.
1684      * @return the internal name of the common super class of the two given
1685      *         classes.
1686      */
1687     protected String getCommonSuperClass(final String type1, final String type2) {
1688         Class<?> c, d;
1689         ClassLoader classLoader = getClass().getClassLoader();
1690         try {
1691             c = Class.forName(type1.replace('/', '.'), false, classLoader);
1692             d = Class.forName(type2.replace('/', '.'), false, classLoader);
1693         } catch (Exception e) {
1694             throw new RuntimeException(e.toString());
1695         }
1696         if (c.isAssignableFrom(d)) {
1697             return type1;
1698         }
1699         if (d.isAssignableFrom(c)) {
1700             return type2;
1701         }
1702         if (c.isInterface() || d.isInterface()) {
1703             return "java/lang/Object";
1704         } else {
1705             do {
1706                 c = c.getSuperclass();
1707             } while (!c.isAssignableFrom(d));
1708             return c.getName().replace('.', '/');
1709         }
1710     }
1711 
1712     /**
1713      * Returns the constant pool's hash table item which is equal to the given
1714      * item.
1715      *
1716      * @param key
1717      *            a constant pool item.
1718      * @return the constant pool's hash table item which is equal to the given
1719      *         item, or <tt>null</tt> if there is no such item.
1720      */
1721     private Item get(final Item key) {
1722         Item i = items[key.hashCode % items.length];
1723         while (i != null && (i.type != key.type || !key.isEqualTo(i))) {
1724             i = i.next;
1725         }
1726         return i;
1727     }
1728 
1729     /**
1730      * Puts the given item in the constant pool's hash table. The hash table
1731      * <i>must</i> not already contains this item.
1732      *
1733      * @param i
1734      *            the item to be added to the constant pool's hash table.
1735      */
1736     private void put(final Item i) {
1737         if (index + typeCount > threshold) {
1738             int ll = items.length;
1739             int nl = ll * 2 + 1;
1740             Item[] newItems = new Item[nl];
1741             for (int l = ll - 1; l >= 0; --l) {
1742                 Item j = items[l];
1743                 while (j != null) {
1744                     int index = j.hashCode % newItems.length;
1745                     Item k = j.next;
1746                     j.next = newItems[index];
1747                     newItems[index] = j;
1748                     j = k;
1749                 }
1750             }
1751             items = newItems;
1752             threshold = (int) (nl * 0.75);
1753         }
1754         int index = i.hashCode % items.length;
1755         i.next = items[index];
1756         items[index] = i;
1757     }
1758 
1759     /**
1760      * Puts one byte and two shorts into the constant pool.
1761      *
1762      * @param b
1763      *            a byte.
1764      * @param s1
1765      *            a short.
1766      * @param s2
1767      *            another short.
1768      */
1769     private void put122(final int b, final int s1, final int s2) {
1770         pool.put12(b, s1).putShort(s2);
1771     }
1772 
1773     /**
1774      * Puts two bytes and one short into the constant pool.
1775      *
1776      * @param b1
1777      *            a byte.
1778      * @param b2
1779      *            another byte.
1780      * @param s
1781      *            a short.
1782      */
1783     private void put112(final int b1, final int b2, final int s) {
1784         pool.put11(b1, b2).putShort(s);
1785     }
1786 }